1. Field of the Invention
The invention relates digital cameras, particularly to lenses of digital cameras.
2. Description of Related Art
A converter lens can be mounted in front of a non-interchangeable lens of a compact digital camera for providing a magnification greater or less than 1 to the lens. A converter lens is telephoto if the magnification thereof is greater than 1, and is wide-angled if that is less than 1. Some converter lenses whose magnification is greater than 2 are used for macrophotography. Conventional macro converter lenses are unsophisticated lenses without light sources. An external light source for macrophotography must be used. It is expensive and not easy to use.
On the other side, in macrophotography, focusing operation is a spiny question. The depth of field in macrophotography is very shallow. Even a slight vibration can make the shot object out of focus when a tripod is not used to associate with the camera. It would be very helpful if both the shot object and a focus distance of a lens can be unvarying.